U.S. patent number 8,272,861 [Application Number 13/104,340] was granted by the patent office on 2012-09-25 for apparatus for vulcanizing at least a tread of a tire.
This patent grant is currently assigned to Titan International, Inc.. Invention is credited to John Fike, Louis T. Fike, Frank Slopko.
United States Patent |
8,272,861 |
Fike , et al. |
September 25, 2012 |
Apparatus for vulcanizing at least a tread of a tire
Abstract
An apparatus for vulcanizing at least a tread of a tire has a
top mold section and a bottom mold section. The mold sections are
secured to one another during a vulcanizing process by a plurality
of locking mechanisms located around the outer circumference of the
apparatus. Each locking mechanism includes a dual action hydraulic
actuator. A piston rod of the hydraulic actuator imparts movement
to a generally vertically oriented articulated linkage member.
T-shaped projection located at an end of the articulated linkage
member distal from the piston rod is brought into engagement with a
securing member associated with the top mold section to secure the
mold sections to one another. After the vulcanizing process is
complete the hydraulic actuator imparts movement to the articulated
linkage member to release the top mold section from the bottom mold
section.
Inventors: |
Fike; Louis T. (Hacienda
Heights, CA), Slopko; Frank (Victorville, CA), Fike;
John (Chino Hills, CA) |
Assignee: |
Titan International, Inc.
(Quincy, IL)
|
Family
ID: |
46846271 |
Appl.
No.: |
13/104,340 |
Filed: |
May 10, 2011 |
Current U.S.
Class: |
425/47;
425/25 |
Current CPC
Class: |
B29D
30/0606 (20130101); B29D 30/0662 (20130101) |
Current International
Class: |
B29C
33/28 (20060101) |
Field of
Search: |
;425/25,47 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mackey; James
Attorney, Agent or Firm: Davis Brown Law Firm Harris;
Emily
Claims
What is claimed is:
1. An apparatus for vulcanizing at least a tread of a tire
comprising: a top mold section and a bottom mold section, said top
mold section being vertically movable with respect to the bottom
mold section from a raised open tire receiving position to a lower
closed vulcanizing position; the top mold section and the bottom
mold section each having a circumferentially extending outer wall,
a plurality of mechanisms for locking the top mold section to the
bottom mold section when the upper mold section is in the lower
closed vulcanizing position are spaced apart around the
circumferentially extending outer walls of the top and bottom mold
sections, the mechanisms for locking the top mold section to the
bottom mold section each comprising: (a) a hydraulic actuator
comprising a cylinder, a piston disposed within the cylinder and a
piston rod having a first end fixed to the piston and extending
through the cylinder to a second end located outside the cylinder,
the hydraulic actuator disposed such that the cylinder is at least
partially disposed below the bottom mold section, the second end of
the piston rod is located radially outward of the circumferentially
extending outer wall of the bottom mold section and is movable
towards and away from the circumferentially extending outer wall of
the bottom mold section, the second end of the piston rod being
fixed to a first end of an articulated linkage member comprising a
plurality of segments connected to one another in a pivotal manner,
a vertically highest segment of the articulated linkage member
having a T-shaped locking projection at a second end of the
articulated linkage member; and (b) an adjustable securing
mechanism fixed directly or indirectly to the circumferentially
extending outer wall of the top mold section and circumferentially
aligned with the T-shaped locking projection, the securing
mechanism having a slot therein that extends radially with respect
to the top mold section for receiving the articulated linkage
member with the T-shaped locking projection located above the slot,
an upper surface of the adjustable securing mechanism having a
concave surface disposed on each side of the slot for receiving a
complementary surface of the T-shaped locking projection.
2. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 wherein the articulated linkage member
comprises the plurality of segments fixed to one another by joints
that allow next adjacent segments of the articulated linkage member
to rotate with respect to a common pivot shaft.
3. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 wherein the T-shaped locking projection is
moved vertically by the articulated linkage member to engage and
disengage from the concave surfaces of the adjustable securing
mechanism.
4. The apparatus for vulcanizing at least a tread of a tire
according to claim 2 wherein the T-shaped locking projection is
moved vertically by the articulated linkage member to engage and
disengage from the concave surfaces of the adjustable securing
mechanism.
5. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 wherein the T-shaped locking projection is
moved into contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction towards the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection vertically upward and in a direction towards the
circumferentially extending outer wall of the top mold section to a
position where the T-shaped locking projection is above and aligned
with the concave surfaces of the adjustable securing mechanism, and
continuing the movement of the piston rod in a direction towards
the circumferentially extending outer wall of the bottom mold
section causing the articulated linkage member to move the T-shaped
locking projection vertically downward into contact with the
concave surfaces of the adjustable securing mechanism.
6. The apparatus for vulcanizing at least a tread of a tire
according to claim 2 wherein the T-shaped locking projection is
moved into contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction towards the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection vertically upward and in a direction towards the
circumferentially extending outer wall of the top mold section to a
position where the T-shaped locking projection is above and aligned
with the concave surfaces of the adjustable securing mechanism, and
continuing the movement of the piston rod in a direction towards
the circumferentially extending outer wall of the bottom mold
section causing the articulated linkage member to move the T-shaped
locking projection vertically downward into contact with the
concave surfaces of the adjustable securing mechanism.
7. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 wherein the T-shaped locking projection is
moved away from contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection vertically upward and away from the circumferentially
extending outer wall of the top mold section.
8. The apparatus for vulcanizing at least a tread of a tire
according to claim 2 wherein the T-shaped locking projection is
moved away from contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection first vertically upward and away from the
circumferentially extending outer wall of the top mold section.
9. The apparatus for vulcanizing at least a tread of a tire
according to claim 5 wherein the T-shaped locking projection is
moved away from contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection first vertically upward and away from the
circumferentially extending outer wall of the top mold section.
10. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 wherein adjustable securing mechanism includes
a wedge and the vertical location of the upper surface of the
adjustable securing mechanism having the concave surface disposed
on each side of the slot for receiving the complementary surface of
the T-shaped locking projection is adjustable by varying the
location of the wedge.
11. The apparatus for vulcanizing at least a tread of a tire
according to claim 1 further comprising a hydraulic power supply
comprising a hydraulic pump and a fluid reservoir, the hydraulic
power supply being in communication with the hydraulic
actuator.
12. An apparatus for vulcanizing at least a tread of a tire
comprising: a top mold section and a bottom mold section, said top
mold section being vertically movable with respect to the bottom
mold section from a raised open tire receiving position to a lower
closed vulcanizing position; the top mold section and the bottom
mold section each including an interior structure for imparting
raised and depressed features to the tread of a tire, and both the
top and bottom mold sections having a circumferentially extending
outer wall, the circumferentially extending outer walls of both the
top and bottom mold sections having a plurality of pairs of
vertically extending mounting brackets spaced apart around the
circumference of the circumferentially extending outer walls; a
hydraulic power supply comprising a hydraulic pump and a fluid
reservoir; a plurality of mechanisms for locking the top mold
section to the bottom mold section when the upper mold section is
in the lower closed vulcanizing position are spaced apart around
the circumferentially extending outer walls of the top and bottom
mold sections, the mechanisms for locking the top mold section to
the bottom mold section each comprising: (a) a dual action
hydraulic actuator in communication with the hydraulic power supply
comprising a cylinder, a piston disposed within the cylinder and a
piston rod having a first end fixed to the piston and extending
through the cylinder to a second end located outside the cylinder,
the dual action hydraulic actuator disposed such that the cylinder
is at least partially disposed below the bottom mold section, the
second end of the piston rod is located radially outward of the
circumferentially extending outer wall of the bottom mold section
and is movable towards and away from the circumferentially
extending outer wall of the bottom mold section, the second end of
the piston rod being fixed at a location between one of the pairs
of mounting brackets on the circumferentially extending outer wall
of the bottom mold segment to a first end of an articulated linkage
member comprising a plurality of segments fixed to one another by
joints that allow next adjacent segments of the articulated linkage
member to rotate with respect to a common pivot shaft, a vertically
highest segment of the articulated linkage member having a T-shaped
locking projection at a second end of the articulated linkage
member; and (b) an adjustable securing mechanism located between
one of the pairs of mounting brackets on the circumferentially
extending outer wall of the top mold section and circumferentially
aligned with the T-shaped locking projection, the securing
mechanism having a slot therein that extends radially with respect
to the top mold section for receiving the articulated linkage
member with the T-shaped locking projection located above the slot,
an upper surface of the adjustable securing mechanism having a
concave surface disposed on each side of the slot for receiving a
complementary convex surface of the T-shaped locking
projection.
13. The apparatus for vulcanizing at least a tread of a tire
according to claim 12 wherein the T-shaped locking projection is
moved into contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction towards the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection vertically upward and in a direction towards the
circumferentially extending outer wall of the top mold section to a
position where the T-shaped locking projection is above and aligned
with the concave surfaces of the adjustable securing mechanism, and
continuing the movement of the piston rod in a direction towards
the circumferentially extending outer wall of the bottom mold
section causing the articulated linkage member to move the T-shaped
locking projection vertically downward into contact with the
concave surfaces of the adjustable securing mechanism.
14. The apparatus for vulcanizing at least a tread of a tire
according to claim 12 wherein the T-shaped locking projection is
moved away from contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection vertically upward and away from the circumferentially
extending outer wall of the top mold section.
15. The apparatus for vulcanizing at least a tread of a tire
according to claim 13 wherein the T-shaped locking projection is
moved away from contact with the concave surfaces of the adjustable
securing mechanism when the top and bottom mold sections are in the
lower closed vulcanizing position by actuating the hydraulic
actuator to move the piston rod in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection first vertically upward and away from the
circumferentially extending outer wall of the top mold section.
Description
FIELD OF THE INVENTION
The present invention relates to a mold and a vulcanization
apparatus for vulcanizing a new tire or a tread of a retreaded
tire.
BACKGROUND OF THE INVENTION
The rubber polymer of a pneumatic tire is vulcanized by placing a
newly constructed tire in a mold and applying heat and pressure to
cause the rubber polymer to be vulcanized and assume a desired
shape and design by pressing the tire against the mold. Tires are
most usually vulcanized with the axis of rotation of the tire
extending vertically, such that a tire mold has mating upper and
lower portions that form the bead and sidewall regions of the tire,
with both the upper and lower mold portions forming a part of the
ground engaging tread region of the tire. While smaller tire molds
may be used with a clam shell type of vulcanization press, very
large tires for farm equipment, earthmoving equipment and similar
applications have the upper and lower portions of the tire mold
configured as separate units that are assembled with one another by
placing a new or retreaded tire in the lower portion of the mold,
then mating the upper portion of the mold to the lower portion
using a crane or hoist. In such an operation the fixing of the
upper and lower mold portions to one another can be very time
consuming and labor intensive, which has a negative effects on
efficiency and cost of production. The present invention provides
an apparatus and method for improving the efficiency and reducing
the cost of vulcanization of very large new or retreaded tires.
DISCUSSION OF THE PRIOR ART
U.S. Pat. No. 6,632,393 B2 teaches a method and apparatus for
vulcanizing large radial pneumatic tires in a segmental mold in a
conventional autoclave without deforming the cords of the belt
package relative to the unvulcanized rubber of the tire. U.S. Pat.
No. 6,716,013 B2 teaches a tear resistant shield that can be used
with the tire mold of U.S. Pat. No. 6,632,393 B2 to overcome damage
to mold components due to friction between those mold components.
Such a mold may be employed in the practice of the invention
disclosed herein.
U.S. Pat. No. 3,154,814 A and U.S. Pat. No. 4,270,887 A teach a
prior art means of securing upper and lower mold sections to one
another using swing bolts and nuts, but this arrangement is very
labor intensive and subject to non-uniform tightening of the nuts
on the swing bolts.
U.S. Pat. No. 4,274,820 A teaches a quick release lock system for a
tire vulcanizing apparatus. The apparatus includes a lower matrix
that receives the lower part of a tire to be cured, and an upper
matrix that receives the upper part of the tire to be cured. The
upper matrix is vertically separable from the lower matrix to
receive the tire. A plurality of lock arms are interposed between
the upper and lower matrices to secure such matrices together
during a tire curing operation. The tire cannot be inflated unless
the lock arms are each firmly secured in place. However, under
extreme pressure (as with swing bolts), this design proves to be an
uneconomical solution to the problems of relieving centerline
pressure when it is time to remove the tire from the mold. A need
for a solution to this problem is a motivation for employing the
invention disclosed herein.
SUMMARY OF THE INVENTION
There is provided in accordance with the present invention an
apparatus for vulcanizing at least a tread of a tire. The apparatus
includes a top mold section and a bottom mold section. The top mold
section is vertically movable with respect to the bottom mold
section from a raised open tire receiving position to a lower
closed vulcanizing position. The top and bottom mold sections each
having a circumferentially extending outer wall. A plurality of
mechanisms are provided for locking the top mold section to the
bottom mold section when the upper mold section is in the lower
closed vulcanizing position. These mechanisms are spaced apart
around the circumferentially extending outer walls of the top and
bottom mold sections. The mechanisms for locking the top mold
section to the bottom mold section each include a hydraulic
actuator having a cylinder with a piston disposed within the
cylinder. A piston rod has a first end fixed to the piston and
extends through the cylinder to a second end located outside the
cylinder. Each hydraulic actuator is disposed such that the
cylinder is at least partially disposed below the bottom mold
section with the piston rod aligned radially with respect to the
bottom mold section. The second end of the piston rod is located
radially outward of the circumferentially extending outer wall of
the bottom mold section and is movable towards and away from the
circumferentially extending outer wall of the bottom mold section.
The second end of the piston rod is fixed to a first end of an
articulated linkage member comprising a plurality of segments
connected to one another in a pivotal manner. A vertically highest
segment of the articulated linkage member has a T-shaped projection
at a second end of the articulated linkage member. An adjustable
securing mechanism is fixed to the circumferentially extending
outer wall of the top mold section and is circumferentially aligned
with the T-shaped locking projection. The adjustable securing
mechanism has a slot therein that extends radially with respect to
the top mold section for receiving the articulated linkage member
with the T-shaped locking projection located above the slot. An
upper surface of the adjustable securing mechanism has a concave
surface disposed on each side of the slot for receiving a
complementary surface of the T-shaped locking projection.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a prior art tire mold showing a top
mold section in a raised open position with respect to a bottom
mold section.
FIG. 2 is a cross section of the prior art tire mold of FIG. 1
showing the top mold section in a lowered position with respect to
the bottom mold section, with the mold sections ready to be
positioned within an autoclave to vulcanize a tire.
FIG. 3 is a schematic side elevation view of a prior art autoclave
utilized to vulcanize at least the treads of tires disposed within
a plurality of the prior art tire molds of FIGS. 1 and 2.
FIG. 4 is a perspective view of a prior art tire vulcanizing
apparatus with the upper and lower mold sections spaced apart, the
apparatus employing a known means of securing the upper and lower
mold sections of a tire mold to each other.
FIG. 5 is a perspective view of the prior art tire vulcanizing
apparatus of FIG. 4 with the upper and lower mold sections secured
to one another by the known means of securing the upper and lower
mold sections of a tire mold to each other.
FIG. 6 is a perspective view of an apparatus according to the
present invention for vulcanizing at least the tread of a tire.
FIG. 7 is an elevation view of the apparatus of FIG. 6.
FIG. 8 is a perspective view of a portion of a mechanism for
locking a top mold section to a bottom mold section in the
apparatus of FIG. 6.
FIG. 9A is a side elevation view of the mechanism for locking a top
mold section to a bottom mold section in a configuration where the
top mold section is locked to the bottom mold section.
FIG. 9B is a side elevation view of the mechanism for locking a top
mold section to a bottom mold section in a configuration where the
top mold section is not locked to the bottom mold section. FIG. 9B
shows the locking mechanism is either just about to complete the
locking procedure or just beginning the unlocking procedure.
FIG. 9C is a side elevation view of the mechanism for locking a top
mold section to a bottom mold section in a configuration where the
top mold section is not locked to the bottom mold section. FIG. 9B
shows the locking mechanism is either just beginning the locking
procedure or completing the unlocking procedure.
FIG. 10 is an exploded view of the portion of the adjustable
mechanism for locking a top mold section to a bottom mold section
that is fixed to the upper mold section.
FIG. 11 is a perspective view of the portion of the adjustable
mechanism for locking a top mold section to a bottom mold section
that is fixed to the upper mold section.
FIG. 13 is a cross-section of the portion of the mechanism for
locking a top mold section to a bottom mold section that is fixed
to the upper mold section with the components adjusted to a second
configuration.
FIG. 12 is a cross-section of the portion of the mechanism for
locking a top mold section to a bottom mold section that is fixed
to the upper mold section with the components adjusted to a first
configuration.
DETAILED DESCRIPTION OF THE INVENTION
U.S. Pat. No. 6,632,393 B2 teaches a method and apparatus for
vulcanizing large radial pneumatic tires in a segmental mold in a
conventional autoclave without deforming the cords of the belt
package relative to the unvulcanized rubber of the tire. In the
tire manufacturing and retreading businesses, it is common to use
the terms "cured" in place of vulcanized, "curing" in place of
vulcanizing, and "green tire" in place of unvulcanized tire, so it
is quite acceptable to find these synonymous terms used in prior
art documents and in the present document interchangeably. U.S.
Pat. No. 6,716,013 B2 teaches a tear resistant shield that can be
used with the tire mold of U.S. Pat. No. 6,632,393 B2 to overcome
damage to mold components due to friction between those mold
components. U.S. Pat. No. 6,632,393 B2 and U.S. Pat. No. 6,716,013
B2 are each incorporated herein in its entirety for the purpose of
teaching tire molds that may be used in the practice of the present
invention.
With reference to FIGS. 1 and 2, the segmental mold 10 taught in
U.S. Pat. No. 6,632,393 B2 includes a top mold section 11 and a
bottom mold section 12. As used herein and in the claims the terms,
"top", "bottom", "upper", "lower", "above", "below", "up", "down"
and other indications of vertical direction or location are
understood to be used with referenced to the parts of a tire mold
or tire vulcanizing apparatus when the tire mold or apparatus is in
its operative configuration. The top mold section 11 is movable
with respect to the bottom mold section 12 between a raised open
position and a lower closed position. The top and bottom mold
sections each contain a plurality of like tread segments 13
arranged in a circular pattern. Each tread segment is coupled to
its associated mold section by a slanted guide rod 14 which allows
the tread segment to slide. Two compression springs (not shown) are
positioned on either side of each guide rod 14 to bias the tread
segments outwardly with respect to the respective mold section.
Each of the tread segments is formed with radially inwardly
extending tread groove-defining lugs 15.
A newly assembled and unvulcanized tire, or a used tire having a
replacement tread portion of unvulcanized rubber, is supported
during the vulcanizing process by an annular tire carrier 16 having
complimentary upper and lower bead rings 26, 27 with surfaces that
conform to the shape of the bead and inner sidewall portions of a
tire 18. A conventional inflatable bladder 28 is clamped between
the bead rings and a vertically extending sleeve 29 that connects
the bead rings 26, 27. The sleeve 29 is provided with a fluid inlet
and outlet fitting (not shown) in a conventional manner.
The bottom mold section 12 is so configured that when the top mold
section 11 is spaced apart from the top mold section, the tread
segments 13 of the bottom mold section 12 are arranged radially
outwardly of the outer diameter of an unvulcanized tire. When the
top mold section 11 is moved to a lower position to engage the
bottom mold section, the tread segments 13 of both the top and
bottom mold sections are automatically moved radially inwardly so
that the tread-defining lugs 15 of the tread segments engage the
unvulcanized crown of the tire 18. As used herein and in the claims
with respect to a tire, a tire mold, or a tire vulcanizing
apparatus, the terms "radial" and "radially" are understood to
refer to directions going towards or away from and perpendicular to
the axis of rotation of a tire either when the tire is located in a
mold or outside a mold. A plurality of guide bars 21 are located
radially outwardly of the tread segments of the top mold section
and extend vertically to extend through a bore in a flange 23 of
the bottom mold section to provide a proper circumferential
alignment of the top and bottom mold sections. When the vulcanizing
process is completed the top mold section 11 is raised and the
upper and lower tread segments 13 automatically move outwardly away
from the vulcanized tire allowing the tire to be freely withdrawn
from the bottom mold section 12 without the tread segments damaging
the tire.
U.S. Pat. No. 6,632,393 B2 teaches that an unvulcanized tire 18 can
be vulcanized in a mold without any deformation between the cords
of the bead package and the unvulcanized rubber of the tire thereby
precluding the formation of discontinuities between the cords and
the unvulcanized rubber surrounding such cords. This feature is
accomplished by extending the lower sidewall of the bottom mold
section 12 substantially the entire distance from the tire bead
area to the periphery of the tread portion of the unvulcanized tire
18. With this arrangement, the sidewalls 32, 33 of the tire are
supported by the bottom mold section that provides a firm platform
for the unvulcanized tire without causing a deformation of the belt
package of the tire. The radially outer portion of the lower
sidewall of the bottom mold section 12 is formed with auxiliary
lugs that define the shoulder portions of the tread of a vulcanized
tire. The lugs 15 of the tread segments 13 and the mold sidewall
auxiliary lugs cooperate to form a complete tread pattern of a
vulcanized tire.
U.S. Pat. No. 6,632,393 B2 teaches that a plurality of the prior
art molds each containing an unvulcanized tire may be arranged in a
conventional autoclave for concurrent vulcanizing of the tires.
Referring now to FIG. 3, there is shown a conventional autoclave 40
extending into a well below the floor 47 of a manufacturing
facility. The autoclave has a heater shell 41 provided with a
removable dome 42. A vertically movable fluid-actuated ram 43
arranged within the heater shell is provided at its upper end with
a mold support platform 44. A pressurized liquid such as water for
operating the ram is provided by piping 45 in a known manner. In
FIG. 3 a plurality of the prior art molds, designated M-1, M-2 and
M-3, have been positioned within the heater shell. The top mold
section of the lowermost mold M-1 will be urged downwardly towards
its closed position by the weight of the second mold M-2 as the
latter is positioned upon mold M-1 within the autoclave 40. In a
similar fashion the weight of the third mold M-3 will partially or
completely close the top mold section of the second mold section
when mold M-2 is lowered onto mold M-1 within the autoclave. Final
closing of the molds M-1, M-2, and M-3 is effected, however, when
the mold sections have been moved upwardly by the ram 43 until the
top of the uppermost mold M-3 is moved into engagement with the
bolster plate 46 formed on the bottom of the dome 42. The ram will
then squeeze each of the mold sections tightly together under great
pressure. After the tires have been vulcanized the molds are
removed from the autoclave and the vulcanized tires withdrawn from
their respective molds.
While conventional autoclaves are still in use, an alternative
system of vulcanizing new tires and the treads of retreaded tires
using free standing tire vulcanizing machines, that unlike
conventional autoclaves are located entirely above the floor of a
manufacturing facility and accommodate only a single tire
vulcanizing mold. Therefore a new means for squeezing the upper and
lower mold sections of a mold used for vulcanizing very large
tires, wherein very high pressure is exerted on internal surface of
the mold portions is needed.
One known means of securing upper and lower mold sections to one
another is disclosed in U.S. Pat. No. 3,154,814 A, which is
incorporated herein in its entirety for the purpose of teaching a
prior art means of securing upper and lower mold sections to one
another. FIG. 4 is a perspective view of the prior art tire
vulcanizing apparatus 60 disclosed in U.S. Pat. No. 3,154,814 A
with the upper 61 and lower 62 mold sections spaced apart. FIG. 5
shows the same tire vulcanizing apparatus 60 at another stage of
the tire vulcanizing process with the upper and lower mold sections
61, 62 secured to one another by the known means of securing the
upper and lower mold sections of a tire mold to each other.
A stand 63 rests on a floor of a manufacturing facility. The lower
mold section 62 rests on the stand 63 and is secured in place with
appropriate fixing means. It is understood that the upper and lower
mold sections shown in FIGS. 4 and 5 may be replaced by the upper
and lower mold sections disclosed in U.S. Pat. No. 6,632,393 B2 as
described above. In FIGS. 4 and 5 the upper and lower mold sections
are firmly secured together by means of a plurality of swing bolts
64 spaced around the perimeter of the lower mold section 62 and
fastening nuts 65 with each of the fastening nuts tightened against
one of a plurality of upper bracket members 66 spaced around the
perimeter of the upper mold section 61. Each swing bolt is provided
at one end with a through opening for pivotal mounting of the swing
bolt on the lower mold section by means of a pin 67 that is
attached to a pair of lower bracket members 68. The lower bracket
members are welded to the circumferentially extending outer surface
of the lower mold section. The free end of each swing bolt is
formed with fastening threads for receiving a nut and fits within
an upper bracket member fastened to the circumferentially extending
outer surface of the upper mold section. Each of the upper and
lower bracket members comprises a pair of oppositely disposed
extending members.
After the upper mold section 61 is lowered into position adjacent
the lower mold section 62 each swing bolt 64 must be pivoted
upwardly and the associated nut 65 is rotated to tighten the nut
against an upper bracket member 66 with sufficient torque to
maintain the upper and lower mold sections in place during the
vulcanization process. Heat and pressure needed for the
vulcanization process is provided both inside the tire via a
bladder and to the exterior of the tire via platens or steam
chambers disposed in the structure of the upper and lower mold
sections in a known manner. After the vulcanization process is
complete each nut must be loosened to move away from the associated
upper bracket member a sufficient distance that the swing bolt can
be pivoted downwardly away from the upper mold section. After all
of the nuts have been loosened and the swing bolts pivoted
downwardly the upper mold section may be lifted upwardly and the
vulcanized tire 18 may be removed from the lower mold section. It
is understood that this system for securing the upper and lower
mold sections to one another is employed for both the vulcanizing
of newly manufactured tires and retreaded tires.
Referring now to FIGS. 6 and 7 there is presented a perspective
view and an elevation view of an apparatus 70 according to the
present invention for vulcanizing at least the tread of a tire. The
apparatus includes a top mold section 71 and a bottom mold section
72. The top mold section has a top wall 73 and a circumferentially
extending outer wall 74. The bottom mold section has a bottom wall
75 and a circumferentially extending outer wall 76. As used herein
and in the claims it is understood that both the top and bottom
mold sections may include on their interiors molding devices that
form the tread and sidewall contours of a new tire, or tire tread
of a tire that is being retreaded, that is to be vulcanized using
the apparatus of the present invention. U.S. Pat. No. 6,632,393 B2,
which has already been incorporated herein in its' entirety,
teaches an example of such a molding device that may be employed in
the practice of the present invention. However, it is to be
understood that any appropriate molding device may be employed with
the top and bottom mold sections of the apparatus disclosed herein.
The top mold section is vertically movable with respect to the
bottom mold section from a raised open tire receiving position to a
lower closed vulcanizing position. When the top mold section is in
a lower closed vulcanizing position circumferentially extending
ledges 78, 79 of the top and bottom mold sections meet along a
parting line. In FIGS. 6 and 7 the usual additional components of a
tire vulcanizing apparatus, such as an annular tire carrier, bead
shaping rings, an inflatable bladder, and a means for clamping the
bladder in place have been omitted for clarity. However, examples
of such components have been presented in FIG. 2, and are more
fully described in U.S. Pat. No. 6,632,393 B2, which has already
been incorporated herein in its' entirety. It is to be understood
that the any appropriate design and arrangement of such components,
selected in accordance with sound engineering practices, may be
employed with an apparatus according to the present invention for
vulcanizing at least the tread of a tire.
It is to be understood that an apparatus according to the present
invention for vulcanizing at least the tread of a tire may be
utilized with a stand for supporting the bottom mold section. An
appropriate means for supplying heat for the vulcanization process
and pressure inside the curing bladder, selected in accordance with
sound engineering practices, may be employed with an apparatus
according to the present invention for vulcanizing at least the
tread of a tire. An example of such a stand for supporting the
bottom mold section and means for supplying heat and pressure is
disclosed herein in FIGS. 4 and 5 and in U.S. Pat. No. 3,154,814 A
which has already been incorporated herein in its entirety.
The prior art method of securing of upper and lower mold sections
using swing bolts and locking nuts during the vulcanizing of large
earthmover or tractor tires is not without drawbacks. The locking
nuts are difficult to tighten with equal torque around the
perimeter of the mold, and the process is very labor intensive.
Loosening of the locking nuts is even more difficult, labor
intensive, and time consuming. The pressure inside a newly
manufactured earthmover tire during the vulcanization process can
be up to five hundred pounds per square inch. When the interior of
the tire is pressurized by high pressure, the bolts or the frame of
the apparatus may yield and be elongated, or the mold segments for
the tread may become somewhat displaced, and a space may open up at
the parting line where the top and bottom mold sections meet. While
this phenomenon occurs during the vulcanizing of both new and
retreaded tires, the very long time required to vulcanize a new
large tire for earthmoving equipment can be up to about seventeen
hours, and when the pressure inside the mold is released the bolts
are still under tension because of flash at the mold parting line.
It is estimated that the space may be up to 3/16 of an inch (0.19
inch) when very large tires for earthmoving equipment are
vulcanized, and the resultant flash at the centerline of the tire
tread is up to 1/4 inch (0.25 inch). During the vulcanizing process
rubber is pushed between the mating surfaces of the upper and lower
mold sections and is vulcanized so quickly that the rubber
generally does not flow any further than about half way across the
mold parting line.
As the rubber is vulcanized the rubber itself generates about seven
hundred and fifty pounds per square inch of force between the upper
and lower mold sections at the parting line. This is why it takes
much more torque to loosen the fixing nuts after the tire is
vulcanized, and why the operators of tire vulcanizing apparatuses
tend to not tighten the molds too tight, which works against them
since the flash at the centerline of the tire tread becomes thicker
and flows further across the mold parting line. The result is a
less efficient use of very expensive molds and tire vulcanizing
equipment and wasted rubber that becomes flash to be trimmed. It is
indeed an engineering challenge to provide an improved apparatus
and method for securing upper and lower mold sections used in the
vulcanization of very large new and retreaded tires that can
improve manufacturing efficiency and reduce waste. An apparatus of
the present invention for vulcanizing at least a tread of a tire
addresses this engineering challenge by providing a plurality of
novel mechanisms for locking the top mold section to the bottom
mold section when the upper mold section is in the lower closed
vulcanizing position.
The mechanisms for locking the top mold section 71 to the bottom
mold section 72 will now be described with reference to FIGS. 6, 7,
8, 9A, 9B and 9C. A hydraulic actuator 80 is disposed such that the
cylinder is at least partially disposed below the bottom mold
section with the piston rod 82 extending outwardly with respect to
the bottom mold section, as best shown in FIGS. 9A, 9B and 9C. The
hydraulic actuator is of the type generally referred to as a dual
action hydraulic actuator. With reference to FIG. 8, the hydraulic
actuator gets its power from a pressurized hydraulic fluid, which
is typically an oil. The hydraulic actuator 80 includes a cylinder
81, a piston 83 disposed within the cylinder and a piston rod 82
having a first end fixed to the piston and extending through the
cylinder to a second end located outside the cylinder. The piston
divides the inside of the cylinder into two chambers 77, 97. A pump
85, shown schematically in FIG. 8, pumps a hydraulic fluid from a
reservoir 86, shown schematically in FIG. 8, through a first
hydraulic line 87 to a chamber 97 on the piston side of the
cylinder to move the piston such that the piston rod extends
further from the cylinder, while simultaneously hydraulic fluid is
forced from a chamber 77 on the piston rod side of the cylinder
through a second hydraulic line 88 back into the reservoir. The
pump pumps hydraulic fluid from the reservoir through a third
hydraulic line 89 to the chamber 77 on the piston rod side of the
cylinder to move the piston such that the piston rod recedes
further into the cylinder, while simultaneously hydraulic fluid is
forced from a chamber 97 on the piston side of the cylinder through
a fourth hydraulic line 90 back into the reservoir. Appropriate
check valves are incorporated in the hydraulic system to prevent
hydraulic fluid from flowing through the hydraulic lines when it is
desired to maintain the position of the piston and piston rod for
an extended period, such as during the vulcanization cycle for a
tire. As will be further explained below, it is the maintaining of
the position of the piston and piston rod for an extended time that
locks the top and bottom mold sections in their respective
positions during the tire vulcanizing process. It is understood
that an apparatus according to the present invention may have a
single pump and reservoir with lines running to each of the
hydraulic cylinders for the plurality of mechanisms for locking the
top mold section to the bottom mold section. Preferably a flow
divider and header control all of the cylinders. However it is
understood that if desired separate pumps and reservoirs may be
used for the hydraulic cylinders of each of for the plurality of
mechanisms for locking the top mold section to the bottom mold
section. A further alternative is to provide multiple pumps and
reservoirs, each serving only a portion of the plurality of
mechanisms for locking the top mold section to the bottom mold
section.
A closed end of the hydraulic cylinder is fixed via a base plate
91, brackets 92 and a pivot pin 93 to a base such as a factory
floor or an appropriate member of a platform that supports the
bottom mold section. The end 95 of the piston rod that is not fixed
to the piston is disposed radially outwardly of the
circumferentially extending outer wall of the bottom mold section.
The second end 95 of the piston rod 82, that is to say the end of
the piston rod that is not fixed to the piston, is fixed to a first
end of an articulated linkage member 100, preferably in a pivotal
manner. Put another way, the piston rod is fixed to the vertically
lower end of the articulated linkage member in a pivotal manner.
The articulated linkage member comprises a plurality of segments
101, 102, 103 fixed to one another by joints that allow next
adjacent segments of the linkage member to rotate with respect to
common pivot shafts 105, 106. A vertically highest segment 103 of
the articulated linkage member is provided with a T-shaped
projection 108 at a second end of the articulated linkage member.
Preferably the T shaped projection 108 is integral with the
vertically highest segment 103 of the articulated linkage member.
While an exemplary embodiment of an articulated linkage member is
shown in the drawings, it is understood that an articulated linkage
member of any appropriate configuration that performs the functions
disclosed herein, selected in accordance with good engineering
practices, may be used in the practice of the present invention
without deviating from the claimed invention.
A plurality of pairs of vertically extending brackets 110 are
spaced apart around the circumference of the circumferentially
extending outer wall 76 of the bottom mold section 72. As shown the
brackets are each a portion of a support gusset that counters the
pressure inside the mold due to pressure inside the tire.
The vertically lowest segment 101 of the articulated linkage member
is disposed between one of the pairs of brackets. As shown the
lowest segment 101 of the articulated linkage member comprises a
pair of spaced apart parallel plates 112 that are held in a fixed
spaced apart relationship by appropriate joining means. The other
segments 102, 103 of the articulated linkage member may be single
bars, some with forks to accommodate pivot pins, or pairs of spaced
apart parallel plates that are held in a fixed spaced apart
relationship by appropriate joining means. As shown each of the
parallel plates 112 of the lowest segment of the articulated
linkage member has a pair of legs 115, 116 that meet at a vertex.
The vertically lowest segment of the articulated linkage member is
held between the brackets by a pivot pin 118 that is located in the
region of a first end of one of the legs 116 and extends through
passages in one of the pairs of brackets and is secured in place by
appropriate fasteners. The piston rod 82 is fixed to the vertically
lowest segment 101 of the articulated linkage member in the region
of a second end of the other leg 116, preferably by a means that
allows the lowest segment of the articulated linkage member to
pivot with respect to the end of the piston rod. The next adjacent
segment 102 of the articulated linkage member is fixed to the
vertically lowest segment 101 using a pivot pin 105 that extends
through passages located in the region of the vertices of the
parallel plates of the vertically lowest segment. The importance of
this structure to the operation of the invention will be explained
later.
Referring now to FIGS. 6-8 and 10-13, a number of pairs of
vertically extending brackets 120, equal to the number of
articulated linkage members, are spaced apart around the
circumference of the circumferentially extending outer wall 74 of
the top mold section 71. As shown the brackets are each a portion
of a support gusset that counters the pressure inside the mold due
to pressure inside the tire. An adjustable securing mechanism 122
is secured between each of the pairs of vertically extending
brackets 120. The adjustable securing mechanism has a slot 123
therein that extends radially with respect to the top mold section
for receiving the uppermost segment 103 of the articulated linkage
member with the T-shaped locking projection 108 located above the
slot. An upper surface of the adjustable securing mechanism has a
concave surface 125 disposed on each side of the slot for receiving
a complementary surface 126 of the T-shaped locking projection
108.
The operation of the new apparatus for vulcanizing at least a tread
of a tire is best understood by referring to FIGS. 8, 9A, 9B and
9C. FIG. 8 is a perspective view of a mechanism for locking a top
mold section to a bottom mold section. FIG. 9A is a side elevation
view of the mechanism in a configuration where the top mold section
is locked to the bottom mold section. FIG. 9B is a side elevation
view of the mechanism in a configuration where the top mold section
is not locked to the bottom mold section and the locking mechanism
is either just about to complete the locking procedure or just
beginning the unlocking procedure. FIG. 9C is a side elevation view
of the mechanism in a configuration where the top mold section is
not locked to the bottom mold section and the locking mechanism is
either just beginning the locking procedure or completing the
unlocking procedure.
The procedure for moving the T-shaped locking projection 108 into
contact with the concave surfaces 125 of the adjustable securing
mechanism 122 in preparation for starting the vulcanization process
when the top and bottom mold sections are in the lower closed
vulcanizing position is shown best by referring first to FIG. 9C,
then FIG. 9B, and then FIG. 9A. The hydraulic actuator 80 is
actuated by pumping fluid into the chamber 77 in the cylinder 81 on
the piston rod side of the cylinder (while simultaneously hydraulic
fluid is forced from a chamber 97 on the piston side of the
cylinder into a reservoir) to move the piston in a direction
towards the circumferentially extending outer wall 76 of the bottom
mold section 72. This causes the articulated linkage member to move
the T-shaped locking projection 108 vertically upward and in a
direction towards the circumferentially extending outer wall 74 of
the top mold section 71 to a position where the T-shaped locking
projection is above and aligned with the concave surfaces 125 of
the adjustable securing mechanism with the uppermost segment 103
extending through the slot 123 in the securing member. It can be
seen in the drawings that the vertically lowest segment 101 of the
articulated member effects the vertical movements of the T-shaped
locking projection. It can further be seen in the drawings that a
motion limiting device 107 associated with the vertically highest
segment 103 of the articulated member limits the movement of the
T-shaped locking projection towards and away from the
circumferentially extending outer wall of the top mold section.
Hydraulic fluid continues to be pumped into the chamber 77 in the
cylinder on the piston rod side of the cylinder to continue to move
the piston in a direction towards the circumferentially extending
outer wall of the bottom mold section causing the articulated
linkage member to move the T-shaped locking projection 108
vertically downward into contact with the concave surfaces 125 of
the adjustable securing mechanism. With the complementary concave
and convex mating surfaces 108, 125 adjacent to one another
increased pressure inside the mold causes these mating surfaces to
stay in contact and aligned with one another which causes the upper
and lower mold sections to remain properly positioned. Once the
mold is closed there is no need to maintain pressure in the chamber
77 in the cylinder on the piston rod side of the cylinder because
the mold is then held closed by mechanical means. It is understood
that the forces exerted by rubber from the tread portion of a very
large tire during the vulcanization process may be forced into a
space between the top and bottom mold sections, but the amount of
flash formed by such rubber should be less than in prior art tire
vulcanizing devices. It is understood that a factor in the amount
of flash generated during the vulcanization process is the amount
of deviation from the specified volume of tread rubber in the new
or retreaded tire being vulcanized.
The vulcanization of a very large new tire or a very large
retreaded tire can take several hours. After the vulcanization
process is completed the T-shaped locking projection 108 can be
moved away from contact with the concave surfaces 125 of the
adjustable securing mechanism in preparation for separating the top
and bottom mold sections and removing the tire from the bottom mold
section.
In the prior art devices described above the flash located at the
parting line of the upper and lower mold sections may exert forces
that make it difficult and more time consuming to release the upper
mold section from the lower mold section. The present invention
improves the efficiency of the manufacturing process by reducing
the time between vulcanizing successive tires. The procedure is
best shown by referring first to FIG. 9A, then FIG. 9B, and then
FIG. 9C. The hydraulic actuator 81 is actuated by pumping fluid
into the chamber 97 in the cylinder on the piston side of the
cylinder (while simultaneously hydraulic fluid is forced from a
chamber 77 on the piston rod side of the cylinder into a reservoir)
to move the piston in a direction away from the circumferentially
extending outer wall 76 of the bottom mold section 72. This causes
the articulated linkage member 100 to move the T-shaped locking
projection 108 vertically upward, to relieve pressure created by
flash at the junction of the upper and lower mold sections, and in
a direction away from the circumferentially extending outer wall 74
of the top mold section 71 to a position where the T-shaped locking
projection 108 is above the concave surfaces 125 of the adjustable
securing mechanism. Hydraulic fluid continues to be pumped into the
chamber in the cylinder on the piston side of the cylinder to
continue to move the piston in a direction away from the
circumferentially extending outer wall of the bottom mold section
causing the articulated linkage member to move the T-shaped locking
projection to a position where the T-shaped locking projection is
no longer vertically aligned with the adjustable securing mechanism
and is further from the circumferentially extending outer wall of
the top mold section than the concave surfaces of the adjustable
securing mechanism. The top mold section may thereafter be hoisted
upwardly and away from the bottom mold section allowing the tire to
be removed from the bottom mold section.
Inasmuch as an apparatus of the present invention used for
vulcanizing very large tires will of necessity have a large
circumference, it is desirable to provide a means for adjusting the
vertical location of the upper surface of each of the adjustable
securing mechanisms to obtain as uniform as is practical clamping
forces around the circumference of the mating surfaces of the top
and bottom mold sections. In the prior art tire vulcanizing devices
discussed above the only way to attain this goal would be using a
torque wrench for tightening each of the nuts on the swing bolts
before beginning each vulcanization procedure. This is time
consuming and labor intensive, which results in lower production
efficiency and higher costs. An apparatus for vulcanizing at least
a tread of a tire according to the present invention has a
plurality of adjustable securing mechanisms 122 fixed to directly
or indirectly to the circumferentially extending outer wall 74 of
the top mold section 71 and circumferentially aligned with the
T-shaped locking projections 108 of the mechanisms for locking the
top mold section to the bottom mold section. It is understood that
the adjustable securing mechanisms could be fixed directly to the
circumferentially extending outer wall of the top mold section.
However it is preferred that as shown in the drawings, especially
with reference to FIGS. 10-13, that each adjustable securing
mechanism be located between a pair of vertically extending
brackets 120 that are fixed to the circumferentially extending
outer wall 74 of the top mold section 71 by welding or during a
casting process.
The securing mechanism includes a base plate 128 having a slot 129
therein that extends radially with respect to the top mold section
for receiving the uppermost segment 103 of the articulated linkage
member with the T-shaped locking projection 108 located above the
slot. The base plate is fixed to the brackets 120 by welding. If
desired the base plate may be additionally fixed to the
circumferentially extending outer wall of the top mold section by
welding. In any case the fixation of the base plate must be very
robust to accommodate the large force that will be imparted to the
base plate. A pair of spaced apart side receiving members 133 are
located adjacent each of the brackets 120 on top of the base plate
128. An adjustable wedge member 131 is located on top of the base
plate 128 interposed between the side members 133. A plate 140 for
receiving the T-shaped projection 108 located at the top of the
articulated linkage member rests on top of the adjustable wedge
member 131 interposed between the side members 133. Both the
adjustable wedge member and the plate for receiving the T-shaped
projection located at the top of the articulated linkage member
have slots 142,143 therein that are aligned with the slot 129 in
the base plate when the adjustable securing mechanism is assembled.
The plate for receiving the T-shaped projection located at the top
of the articulated linkage member has a concave surface 125
disposed on each side of the slot for receiving a complementary
convex surface 126 on the bottom side of the T-shaped locking
projection. The vertical locations of the concave surfaces are
adjustable as shown for example by dimensions X and Y in FIGS. 12
and 13 using height adjustment screws 145 that screw into the side
members 133. The plate 140 for receiving the T-shaped projection
located at the top of the articulated linkage member is secured in
place with fixing screws 147 that extend horizontally through the
brackets 120 and side members 133. A vertically oriented fixing
screw 149 extends through a passage in the plate for receiving the
T-shaped projection located at the top of the articulated linkage
member and a slot 150 in the adjustable wedge member and screws
into the base plate. It is anticipated that while occasional height
adjustments may be required during the useful life of the
vulcanizing apparatus, this adjustable securing mechanism will be
much less labor intensive and time consuming than imparting a
specified amount of torque on each of the nuts on the prior art
swing bolt arrangements.
It will be seen that the advantages set forth above, and those made
apparent from the foregoing description, are efficiently attained
and since certain changes may be made in the above construction
without departing from the scope of the invention, it is intended
that all matters contained in the foregoing description or shown in
the accompanying drawings shall be interpreted as illustrative and
not in a limiting sense. It is also to be understood that the
following claims are intended to cover all of the generic and
specific features of the invention herein described, and all
statements of the scope of the invention which, as a matter of
language, might be said to fall there between.
* * * * *